Birth outcomes and early growth patterns associated with age at adiposity rebound: the Ma’anshan birth cohort (MABC) study

Objective Early onset of adiposity rebound (AR) is considered an early indicator of obesity risk. Our objective was to investigate the association of birth outcomes and early physical growth patterns with early AR in children. Methods Study subjects (n = 2705) were enrolled from the Ma’anshan birth cohort (MABC). The body mass index (BMI), head circumference, waist circumference, and body fat were collected. Rapid weight gain (RWG) was defined by the change in weight standard-deviation score in the first two years of life. Group-based trajectory modeling (GBTM) was used to determine children’s physical growth trajectories. The age of AR was fitted using fractional polynomial function models. Results Children with very high BMI trajectories (RR = 2.83; 95% CI 2.33 to 1.40), rising BMI trajectories (RR = 3.15; 95% CI 2.66 to 3.72), high waist circumference trajectories (RR = 4.17; 95% CI 3.43 to 5.06), and high body fat trajectories (RR = 3.01; 95% CI 2.62 to 3.46) before 72 months of age were at a greater risk of experiencing early AR. Low birth weight (LBW) (RR = 1.86; 95% CI 1.28 to 2.51), preterm birth (PTB) (RR = 1.50; 95% CI 1.17 to 1.93), and small for gestational age (SGA) (RR = 1.37; 95% CI 1.14 to 1.64) associated with increased risk of early AR. Moreover, infants experiencing RWG (RR = 1.59; 95% CI 1.40 to 1.83), low BMI trajectories (RR = 1.27; 95% CI 1.06 to 1.53) and rising BMI trajectories (RR = 1.50; 95% CI 1.22 to 1.84) in the first two years were at higher risk of developing early AR subsequently. Compared to the group with non-early AR, the BMI of children with early AR tended to be lower first (from birth to 6 months of age) and then higher (from 18 to 72 months of age). Conclusions Children with overall high BMI, high waist circumference, and high body fat before 72 months of age are more likely to experience early AR, but infants with low BMI trajectories, rising BMI trajectories and infants experiencing RWG in the first two years of life similarly increase the risk of early AR. These results can help to understand the early factors and processes that lead to metabolic risks. Supplementary Information The online version contains supplementary material available at 10.1186/s12889-023-17236-9.


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Table S3 The basic characteristics of participants with and without early AR.

Characteristics
Children with early AR   Table S8 Sensitivity analysis on the association between the trajectories of physical growth and early AR in children.

Figure S4
Trajectories fitted using raw BMI data.

Model 2 :
Adjusted for maternal age, family monthly income per capita, maternal education level, paternal education level, maternal pre-pregnancy BMI, paternal BMI, parity, maternal metabolic dysfunctions during pregnancy, alcohol use during pregnancy, tobacco use during pregnancy, iron supplementation during pregnancy, folic acid supplementation during pregnancy, and children's sex.*: P <0.05; **: P <0.01.

Figure
Figure S1 Directed acyclic graph of the relationship between birth outcome/early growth patterns and age at AR.

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Figure S2 The overall trajectory plot based on the BMI fit of 2705 children.

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Figure S3 Physical growth trajectory of children in the early AR (EAR) and non-early AR (NEAR) groups.

Table S2
Age at AR in children with different birth outcomes.

Table S4
Physical growth levels of children in the early AR and non-early AR groups at each age.
Abbreviations: BMI: body mass index; early AR: early adiposity rebound.†: T-test for early AR group vs. non-early AR group.

Table S5
Proportions of EAR and NEAR in children with different physical trajectories.

Table S6
Sensitivity analysis on the association between birth outcomes and early AR.Sensitivity analysis 1: adjusted for maternal age, family monthly income per capita, maternal education level, paternal education level, maternal pre-pregnancy BMI, paternal BMI, parity, maternal metabolic dysfunctions during pregnancy, alcohol use during pregnancy, tobacco use during pregnancy, iron supplementation during pregnancy, folic acid supplementation during pregnancy, children's sex, and exclusive breastfeeding duration ≥6 months.Sensitivity analysis 2: adjusted for maternal age, family monthly income per capita, maternal education level, paternal education level, maternal pre-pregnancy BMI, paternal BMI, parity, maternal metabolic dysfunctions during pregnancy, alcohol use during pregnancy, tobacco use during pregnancy, iron supplementation during pregnancy, folic acid supplementation during pregnancy, children's sex, main caregivers before 3 years, screen time, and outdoor activity time.

Table S7
Sensitivity analysis on the association of RWG, BMI trajectories and head circumference trajectories with early AR.adjusted for maternal age, family monthly income per capita, maternal education level, paternal education level, maternal pre-pregnancy BMI, paternal BMI, parity, maternal metabolic dysfunctions during pregnancy, alcohol use during pregnancy, tobacco use during pregnancy, iron supplementation during pregnancy, folic acid supplementation during pregnancy, children's sex, and exclusive breastfeeding duration ≥6 months.
Abbreviations: BMI: body mass index; RWG: rapid weight gain; Early AR: early adiposity rebound.Sensitivity analysis 1: Sensitivity analysis 1: adjusted for maternal age, family monthly income per capita, maternal education level, paternal education level, maternal pre-pregnancy BMI, paternal BMI, parity, maternal metabolic dysfunctions during pregnancy, alcohol use during pregnancy, tobacco use during pregnancy, iron supplementation during pregnancy, folic acid supplementation during pregnancy, children's sex, and exclusive breastfeeding duration ≥6 months.
Sensitivity analysis 2: adjusted for maternal age, family monthly income per capita, maternal education level, paternal education level, maternal pre-pregnancy BMI, paternal BMI, parity, maternal metabolic dysfunctions during pregnancy, alcohol use during pregnancy, tobacco use during pregnancy, iron supplementation during pregnancy, folic acid supplementation during pregnancy, children's sex, main caregivers before 3 years, screen time, and outdoor activity time.*: P <0.05; **: P <0.01.

Table S9
Associations of BMI trajectories (using raw BMI data) and early AR in children.